THERE ARE TWO TYPES OF SUNSCREEN BLOCKERS AVAILABLE: PHYSICAL (ALSO COMMONLY REFERRED TO AS “MINERAL”) AND CHEMICAL.
Physical sunscreens use UV filters that scatter, reflect and block the sun’s rays. Chemical sunscreen use active ingredients that interact with the skin’s top layer to absorb UV rays and convert their energy. Once this energy is absorbed, the energy is diffused into the skin as heat.
Zinc Oxide and Titanium Dioxide are the two options for physical blockers. We use non-nano Zinc Oxide for our sunscreens, and here’s why:
- Titanium Dioxide works as a hybrid by scattering and absorbing UVA1 and UVB rays.
- Zinc Oxide sits on top of the skin, creating a physical barrier that both reflects UV rays away from the skin and effectively blocks UVA1, UVA2 and UVB rays. It does not absorb into living skin cells.
- Zinc Oxide is the only FDA approved Broad Spectrum UVA/UVB Protection ingredient.
- Zinc oxide is EWG’s first choice for sun protection.
- Zinc Oxide is stable in sunlight and won’t degrade or lose potency over time.
- Zinc oxide does not produce skin sensitivities and rashes nor does it initiate the creation of free radicals or hormone disruptors.
- Non Nano zinc oxide is the only reef safe active
- Most Titaniums are Nano and coated with chemical/aluminum treatments
Chemical sunscreens tend to use a combination of ingredients to protect against the full spectrum of UV rays, as individually they all filter different ranges of the spectrum. Some of the chemicals used pass entirely through the bloodstream and have been linked to hormone disruption.
- Avobenzone: It’s used in sunscreens because it absorbs UV radiation. Since it cannot destroy this energy, it has to convert the light energy into chemical energy, which is normally released as free radicals. In sunlight, avobenzone degrades and becomes ineffective within an hour.
- Benzophenone: Scientists discovered that this chemical mimics estrogen. They recommended more studies to look at possible long-term effects as a hormone disruptor.
- Homosalate / Octyl Methoxycinnamate / Octinoxate: These are all common sunscreen ingredients that have shown estrogenic activity in lab tests. They’ve been shown to disrupt hormones, affect the development of the brain (particularly the hypothalamo-pituitary-gonadal system) and of reproductive organs in laboratory rats.
- Oxybenzone: This chemical has the highest percentages of skin penetration, enters the bloodstream, bioaccumulates and acts like estrogen in the body. A study from the Centers for Disease Control (CDC) found that it has been linked to allergies, hormone disruption, low birth weight and cell damage. Another big concern with this chemical is that it damages the DNA in juvenile corals and creates bleaching events.
- PABA (para-aminobenzoic acid): It was one of the first chemical actives used in early formulas. It is less common in newer sunscreens as it can cause red, itchy skin.
Other non-active ingredients commonly found in chemical sunscreens:
- BHA and BHT: Used mainly in moisturizers and makeup as preservatives, these chemicals have been suspected as endocrine disruptors, may cause cancer and are harmful to fish and wildlife.
- Carbomers: Found in many cosmetic products, these are synthetic polymers made from acrylic.
- Ethyl Alcohol / Ethanol: Common in health and beauty products and often found in after-sun care, even at low concentrations, ethanol may induce apoptosis in skin cells and cause skin irritation, contact dermatitis and the absorption of carcinogenic contaminants. Also avoid: denatured alcohol, methanol, benzyl alcohol, isopropyl alcohol.
- Formaldehyde-Releasing Preservatives: DMDM hydantoin, diazolidinyl urea, imidazolidinyl urea, methenamine and quarternium-15 all slowly release small amounts of formaldehyde, which causes cancer and skin irritation.
- Fragrances or Perfume: 95% of the chemicals in fragrances are synthetic compounds derived from petroleum. Some of these chemicals can alter the skin’s surface tension, allowing more chemicals to be absorbed through the skin. Fragrance chemicals affect the brain and nervous system, with some effects being immediate and transitory; others being chronic and long lasting. Fragrances can modify brain blood flow, alter blood pressure, act as irritants / allergens, trigger migraine headaches, induce or worsen respiratory problems and trigger asthma in children.
- Nanoparticles: Widely used in consumer products, these are particles of different matter at the molecular level. When applied to the skin, atoms can enter the body through damaged skin and cause harm to the body.
- Parabens: These preservatives mimic estrogen and act as potential hormone (endochrine) system disruptors. Along with cinnamate, benzophenone, and camphor derivatives, parabens activate algae viruses and contribute to coral bleaching.
- Photosensitizers: Most citrus (orange, grapefruit, lemon) can increase the chance of getting burned when applied to the skin as well as some antibiotics. It’s important to check before going in the sun.
- Propylene Glycol and Butylene Glycol: These petroleum plastics act as surfactants (wetting agents, solvents). The EPA considers Propylene Glycol so toxic it requires protective gloves, clothing, goggles and disposal by burying. Because Propylene Glycol penetrates the skin so quickly, the EPA warns against skin contact to prevent brain, liver, and kidney abnormalities. Surprisingly, it’s one of the most common ingredient in personal care products.
- Vitamin A (Retinyl Palmitate, Retinol, Retinyl Acetate, Retinyl Linoleate, Retinoic Acid): Too much pre-formed vitamin A can cause a variety of health problems, including liver damage, brittle nails, hair loss, osteoporosis and hip fractures in older adults. A study by U.S. government scientists suggests that retinyl palmitate may speed the development of skin tumors and lesions when applied to the skin in the presence of sunlight. Excessive vitamin A can cause serious skeletal birth defects in a developing fetus.